1. Field of the Disclosure
The present invention relates to a backlight unit having reflective portions.
2. Discussion of the Related Art
In general, as a typical large sized display device, there are LCD (Liquid Crystal Display Device), PDP (Plasma Display Panel) and so on.
Different from a spontaneous light emission type PDP, since the LCD has no light emission device for itself, the LCD requires a separate backlight unit, essentially.
In the backlight unit of the LCD, there are an edge light type backlight unit, and a direct light type backlight unit depending on positions of a light source of the backlight unit, wherein, since the edge light type has the light source arranged at a left or right side or an upper or lower side of the LCD panel for distribution of a light throughout an entire surface of the screen by using a light guide plate, the edge light type has good light uniformity and enables to fabricate a thin display device.
Since the direct light type, which is a technology used in general for the display device greater than 20″, has a plurality of the light sources arranged on a lower side of the panel, the direct light type has an advantage in optical efficiency over the edge light type to use in the large sized display device that requires high brightness, mostly.
As the light source of the related art edge light type or direct light type backlight unit, a CCFL (Cold Cathode Fluorescent Lamp) is used.
However, since the backlight unit of CCFL has power always applied to the CCFL, the backlight unit has drawbacks in that a substantial amount of power is consumed, a color reproduction ratio is about 70% level compared to a CRT, and mercury contained in the CCFL causes environmental contamination.
As a substitutional product for solving above problems, active researches on the backlight unit with an LED (Light Emitting Diode) are underway, presently.
If the LED is used in the backlight unit, since local turn on/off is possible, substantial reduction of power consumption is possible, and RGB LEDs having a color reproduction range well over 100% of the NTSC (National Television System Committee) specification can provide a lively picture to consumers.
Moreover, it is a feature that the LED manufactured by a semiconductor fabrication process is harmless to the environment.
Though LCD products which adopt the LED that has above advantages appear in succession, since the products have driving mechanisms different from the related art CCFL light source, the drivers, and PCB boards are expensive.
Consequently, the LED backlight unit is applied only to high price LCD products, still.